apparmor: Fix ref count leak in task_kill

apparmor_task_kill was not putting the task_cred reference tc, or the
cred_label reference tc when dealing with a passed in cred, fix this
by using a single fn exit.

Fixes: 90c436a6 ("apparmor: pass cred through to audit info.")
Signed-off-by: John Johansen <john.johansen@canonical.com>

security/apparmor/lsm.c

@@ -954,7 +954,6 @@ static int apparmor_task_kill(struct task_struct *target, struct kernel_siginfo
 		cl = aa_get_newest_cred_label(cred);
 		error = aa_may_signal(cred, cl, tc, tl, sig);
 		aa_put_label(cl);
-		return error;
 	} else {
 		cl = __begin_current_label_crit_section();
 		error = aa_may_signal(current_cred(), cl, tc, tl, sig);